'There are players who cheat and sell their souls to the devil. That is exactly what it amounts to. Maybe they'll be able to run a little bit faster or longer, but what about their health?

'If at 40 years of age you find yourself with a tumour, what good does it do you to have scored a few more goals or earned a few more millions? What use is it?'

Vialli's attack, in an Italian Catholic weekly publication, comes at a time of turmoil in football, both in his native Italy and elsewhere abroad.

Barcelona's Frank De Boer, Edgar Davids of Juventus and Lazio's Fernando Couto are facing long bans for allegedly taking the steroid nandrolone and Vialli, himself, was accused and later cleared of using improper substances while at Juve.

Vialli said: 'I thought about it a lot after the recent cases of nandrolone. I refuse to believe that, after the first few cases, anyone could be so stupid as to continue taking it, knowing they could get caught at any time.

'There is something bigger going on, something over which the players, in some cases, have little control. The Press is responsible, too. They're ready to write about everything except the very issues which they know all about but are afraid to bring to light.'

He added that players, while handsomely rewarded, did not have enough of a say in how the sport is being run.

Vialli, who yesterday signed two defenders - Marseille captain Patrick Blondeau, 33, and Brescia's 38-year-old Filippo Galli - on free transfers for Watford, also revealed that his sacking from Chelsea had taught him a lot about management.

He said: 'At Chelsea I coached players who struggled to understand that my role had changed. I was no longer their team-mate, I was their boss.

'In my mind, the individual personal relationships had not changed, just the professional ones. But some, I fear, did not understand that. They wanted the professional relationship to remain unchanged and I could not allow that.

'It was an important lesson. Recently I've been reading a number of books about psychology and management and how they tie in with sports.

'I want to improve my ability to manage people, not just players. The best managers know how to do this, it is the single most important aspect of management. Tactics, training techniques, everything else comes after that.'